package b面向对象.day1.demo2;

public class Test {
    public static void main(String[] args) {
        Stu s=new Stu();
        Teacher t=new Teacher();
        s.t=t;
        //s=null;
//        System.out.println(s.t);//null
//        System.out.println(s.t.name);
        s.study() ;
    }
}
